A single photon source is a light source which is adjusted to repetitively emit single photons at a specific repetition rate. It can be used e.g. in optical quantum cryptography. One way of realizing a single photon source is to attenuate a laser beam down to a level where emitted photons are statistically separated with a sufficient probability. However, such a source suffers from random fluctuations in the photon emission rate which means major drawbacks for a use as an optical telecommunication device. According to another type of single photon source an optically or electrically driven emission from a single quantum dot is used. An example of an optically driven quantum dot photon source is given in GB 2377551 A. Although single quantum dot sources are advantageous in respect of their compactness they include the drawback of a poor collection efficiency and a low repetition rate. Moreover, it is difficult to fabricate arrays of multiple quantum dots with precisely predetermined positions of the dots with present manufacturing methods such as self-assembling techniques.
It is an object of the present invention to provide a single photon source with a high collection efficiency and repetition rate and which can be manufactured with high precision and reproducibility as well as a corresponding method.